Compile fix for platforms without process support

Change-Id: Iaf15ecd49524a787198d091399454c3daeeeb51b
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>
Use qreal for equalOrNaN(), exclusiveNaN() helpers in QML import plugin.

Fix g++-warnings:
qdeclarativeposition.cpp:95:6: warning: 'bool {anonymous}::equalOrNaN(float, float)' defined but not used
qdeclarativeposition.cpp:105:6: warning: 'bool {anonymous}::exclusiveNaN(float,float)' defined but not used

Change-Id: I430864ebbf31592fd1a1cfc5e2f52af7cedc708e
Reviewed-by: Aaron McCarthy <mccarthy.aaron@gmail.com>